Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already flag destructiveHint=true and idempotentHint=false, but the description earns credit by specifying exactly what is destroyed ('Running it again replaces the whole plan, edits included') and disclosing cost/latency ('The longest step (several minutes)') that annotations cannot express. This is behaviorally richer than the structured hints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the verb and the plan's contents, then moves to prerequisites, behavior, and runtime. It is dense and slightly run-on with stacked parentheticals ('(its timing drives the cuts)', '(several minutes)'), but every clause carries information rather than filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers the prerequisite, the conditional media behavior, the destructive re-run semantics, and the monitoring loop, which is substantial for a four-parameter mutation with no output schema. It does not describe the shape of the returned plan, which is the main remaining gap for an agent consuming the result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents project_id, model, settings, and editable_sections. The description adds no syntax or format details for any parameter (e.g. nothing on how editable_sections maps to the mentioned [SCENE: ...] directions), so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Plan the storyboard') and enumerates the exact artifacts produced: segments, timing, image and motion prompts, overlays, continuations. It also distinguishes itself from the edit/read siblings by noting that clips come later and that re-running replaces the plan, so an agent can separate it from storyboard_edit, render, and storyboard_read without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a concrete prerequisite ('Needs the finished voiceover (its timing drives the cuts)') and conditional scope ('real photos and B-roll when the director style has the @real-media tag'), plus a monitoring instruction ('get_status wait=true, repeatedly'). No sibling tool is named as an alternative, so it stops short of explicit when-not routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.